The paper aims to analyze relations between the farm size and return from investment in the vegetable forcing sector in Hungary. The most favourable results were gained in the case of plastic foil covered greenhouses heated by thermal water without pumping back, which met the requirements of practice at I ha farm size. The variations of the plastic foil covered greenhouses heated by thermal water with pumping back, coal or wooden chips were regarded as suitable concerning risk taking when the size reached or exceeded 3 ha. The versions of glasshouses heated by thermal water resulted in acceptable profits on 3 ha while their vegetable forcing models heated by coal or wooden chips on S ha or more.
The purpose of this work was the evaluation of yielding and the content of some chemical ingredients of Japanese bunching onion yield obtained from forcing in greenhouse conditions. Plants used for forcing were from field cultivation and had the pseudostem trimmed in the autumn of each year (2002, 2003 and 2004) at the height of 2-4 and 8-10 cm. In the spring of the following year (2003, 2004 and 2005) from the middle of March, the plants were forced in a heated greenhouse (temperature 16-20°C) and an unheated one (temperature 6-12 °C). The whole yield was evaluated when the plants reached the market size for bunching. The weight and height were determined in the plants, as well as the number of laterals and leaves in clusters. In green shoots and the pseudostem, the content of dry weight, total and reducing sugars, L-ascorbic acid, flavonoids and phenolic acids were determined. Very high yield of plants useful for bunching was obtained (average 13.7 kg·m⁻² of area). The plants with a longer pseudostem before forcing yielded better. The conditions of forcing did not have a significant influence on the size of the obtained yield, but the content of L-ascorbic acid and flavonoids was much higher (especially in green shoots) in the plants from forcing in the unheated greenhouse. Lower temperature at the time of forcing was favorable to higher reducing sugar content, especially in the pseudostem. Japanese bunching onion turned out to be useful for forcing for harvest in bunching form.
An assessment was made of the usefulness for forcing of five cultivars of Hyacinthus orientalis L.: ‘Carnegie’, ‘City of Haarlem’, ‘Delft Blue’, ‘Jan Bos’, and ‘Lady Derby’. The bulbs were planted on 14 October 2003 and 2004 in Flexy-tray type of pallets filled with water and in plastic boxes with a standard medium. The bulbs were cooled for 12 or 14 weeks. It was found that forcing lasted shorter in the water-filled trays, while longer inflorescence stems were obtained in plants forced in the standard medium. The cooling of the bulbs for 14 weeks resulted in the shortening of the forcing time and in the lengthening of inflorescence stems.